[clang-tidy] Omit cases where loop variable is not used in loop body in
performance-for-range-copy check.
Summary:
The upstream change r336737 make the check too smart to fix the case
where loop variable could be used as `const auto&`.
But for the case below, changing to `const auto _` will introduce
an unused complier warning.
```
for (auto _ : state) {
// no references for _.
}
```
This patch omit this case, and it is safe to do it as the case is very rare.
Reviewers: ilya-biryukov, alexfh
Subscribers: xazax.hun, cfe-commits
Differential Revision: https://reviews.llvm.org/D50447
git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@339415 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
